Effects of Synoptic Surveillance on model forecasts for
11 August 2004 1800 UTC
Bonnie.


Quicktime movie of AVN DLM wind model forecast
Quicktime movie of DLM wind data increment


TRACK AND INTENSITY PERFORMANCE

TRACK (km)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN234314375550678
AVNO 68 271296325513
%IMP71%14% 21%41%24%
GFNO 10 31124209
GFDL 32 78180250
%IMP-220% -152% -45%-20%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-36-28-12 -2 -4
AVNO-32-19-11 -5 -8
%IMP11%34% 8%-150%-100%
GFNO 17 36 19 19
GFDL 1 37 23 14
%IMP94%-3%-21%26%

Landfall forecasts

12/1400 UTC 29.6N 85.1W St. Vincent/St. George Is., FL 26.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.1989.0012.5380.2Pilottown, LA
AVNO29.1388.9218.0373.5Port Eads, LA
%IMP 41% 2%
GFNO29.8785.4227.5 43.0St. Joe Beach, FL
GFDL30.1085.4929.0 67.1Panama City, FL
%IMP-100% -56%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 11 August 2004 1200 UTC (Tropical Storm Bonnie).

Figure 2. Track forecasts for the no dropwindsonde (NO or NN) and the all dropwindsonde (AL) runs for the AVN and GFDL models initialized on 11 August 2004 1200 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 11 August 2004 1200 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 11 August 2004 1200 UTC.